Formation of CT complexes and electron transfer from excited molecules of anthracene derivatives to methylviologen in aqueous and micellar media

1987 ◽  
Vol 52 (7) ◽  
pp. 1658-1665
Author(s):  
Viktor Řehák ◽  
Jana Boledovičová
Keyword(s):  
Electron Transfer ◽  
Complex Formation ◽  
Fluorescence Quenching ◽  
Rate Constant ◽  
Formation Constants ◽  
Dynamic Quenching ◽  
Micellar Media ◽  
Complex Formation Constants ◽  
Anthracene Derivatives ◽  
Ct Complexes

Disodium 1,5- and 1,8-anthracenedisulphonate (ADS) and 9-acetylanthracene form coloured CT complexes with methylviologen (MV2+) in aqueous and micellar media. The complex formation constants and molar absorptivities were determined by the Benesi-Hildebrandt method. In the fluorescence quenching, its static component plays the major role. The dynamic quenching component is determined by the rate constant of electron transfer from the S1 state of ADS to MV2+.

Host–Guest interaction of pesticide bifenox with cyclodextrin molecules. An electrochemical study

2009 ◽  
Vol 74 (11-12) ◽  
pp. 1647-1664 ◽  
Author(s):  
Magdaléna Hromadová ◽  
Romana Sokolová ◽  
Lubomír Pospíšil ◽  
Štěpánka Lachmanová ◽  
Nicolangelo Fanelli ◽  
...  
Keyword(s):  
Complex Formation ◽  
Anion Radical ◽  
Formation Constants ◽  
Aprotic Solvents ◽  
Reduction Wave ◽  
Nitroaromatic Compound ◽  
Complex Formation Constants ◽  
Oh Groups ◽  
Stable Anion ◽  
Main Factor

The reduction of nitroaromatic compound bifenox (methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate) was studied in aprotic solvents in the absence or presence of cyclodextrin (CD) molecules of different cavity sizes. βCD and γCD form complexes with bifenox in DMSO with the complex formation constants (5 ± 2) × 102 M–1 [βCD–bifenox] and (3 ± 1) × 102 M–1 [γCD–bifenox], respectively. Bifenox yields a relatively stable anion radical in dimethyl sulfoxide, which is further reduced at more negative potentials by an overall addition of three electrons and four protons to the corresponding phenylhydroxylamine. In the presence of βCD the first reduction wave of bifenox becomes irreversible, it is shifted towards more positive potentials and the uptake of more than one electron is observed (up to four electrons during the exhaustive electrolysis). The first reduction wave of bifenox is not affected by the addition of glucose confirming that a simple availability of protons from the OH groups is not the main factor in further transformation of anion radical in the presence of βCD. The complex formation with βCD facilitates the protonation and additionally protects the molecule from disintegration into 2,4-dichlorophenol. A yield of 2,4-dichlorophenol decreases in the order βCD, γCD and αCD, respectively.

On the Fluorescence Quenching of Polycyclic Aromatic Hydrocarbons by Nitromethane

1975 ◽  
Vol 30 (10) ◽  
pp. 1311-1314 ◽  
Author(s):  
H. Dreeskamp ◽  
E. Koch ◽  
M. Zander
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Fluorescence Quenching ◽  
Rate Constant ◽  
Aromatic Hydrocarbons ◽  
High Energy ◽  
Dynamic Quenching ◽  
Quenching Mechanism ◽  
Polycyclic Aromatic ◽  
Acetonitrile Solutions ◽  
Alternant Hydrocarbons

Abstract Fluorescence quenching of 22 polycyclic aromatic hydrocarbons by nitromethane in toluene and acetonitrile solutions has been studied. Contrary to Sawicki’s observations that the fluorescence of hydrocarbons with the fluoranthene skeleton is not quenched that of 11.12-and 3.4-benzofluor-anthene and fluoranthene itself is quenched. These compounds have a high energy of the fluorescence transition. The fluorescence quenching of the compounds investigated follows a dynamic quenching mechanism. The bimolecular rate constant of fluorescence quenching increases exponentially with the energy of the fluorescing state of alternant hydrocarbons.

Complex formation and solubility of Pu(IV) with malonic and succinic acids

2009 ◽  
Vol 97 (4-5) ◽  
Author(s):  
Takayuki Sasaki ◽  
Taishi Kobayashi ◽  
I. Takagi ◽  
Hirotake Moriyama ◽  
A. Fujiwara ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Solvent Extraction ◽  
Complex Formation ◽  
Extraction Method ◽  
Formation Constants ◽  
Complex Formation Constants ◽  
Solvent Extraction Method ◽  
Experimental Solubility Data ◽  
Experimental Solubility ◽  
Solubility Products

AbstractThe complex formation constants of tetravalent plutonium ion with malonic and succinic acids in aqueous solution were determined by the solvent-extraction method. Also, by taking the known values of the solubility products, the hydrolysis constants and the formation constants, the experimental solubility data of plutonium in the presence of carboxylates were analyzed.

Comparison of calcium complexation of some carboxylic acids derived from D­glucose and D-fructose

1995 ◽  
Vol 73 (8) ◽  
pp. 1338-1347 ◽  
Author(s):  
Hélène Bazin ◽  
Gérard Descotes ◽  
Alain Bouchu ◽  
Michelle Petit-Ramel
Keyword(s):  
Molecular Structure ◽  
Complex Formation ◽  
Carboxylic Acids ◽  
Formation Constants ◽  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Complex Formation Constants ◽  
Calcium Complexation ◽  
C Nmr

The aim of this work was to compare calcium sequestering behaviour of 11 carboxylic acids derived from carbohydrates, and to study the influence of molecular structure on the calcium complexation. For this purpose, various carboxylic acids derived from methyl D-glucopyranoside, methyl D-fructopyranoside, and methyl D-fructofuranoside were synthesized and studied using an ion selective electrode to determine calcium complex formation constants. Complexation sites of carbohydrate skeletons were determined using 13C NMR. Keywords: Ca(II) complexation, carboxylic acids, fructofuranosides, fructopyranosides, glucopyranosides.

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